Question: A copy machine is used to make n pages of copies per day. The machine has two trays in which paper gets loaded, and each page used is taken randomly and independently from one of the trays. At the beginning of the day, the trays are refilled so that they each have m pages.
(a) Let pbinom(x, n, p) be the CDF of the Bin(n, p) distribution, evaluated at x. In terms of pbinom, find a simple expression for the probability that both trays have enough paper on any particular day, when this probability is strictly between 0 and 1 (also specify the values of m for which the probability is 0 and the values for which it is 1).
(b) Using a computer, find the smallest value of m for which there is at least a 95% chance that both trays have enough paper on a particular day, for n = 10, n = 100, n = 1000, and n = 10000.